Lunar rocks brought to Earth by China's Chang'e 5 show Moon's volcanoes were recently* active The Moon remained volcanically active much later than previously thought, judging from fragments of rocks dating back two billion years that were collected by China's Chang’e 5 spacecraft. The Middle Kingdom's space agency obtained about 1.72 kilograms (3.8 pounds) of lunar material from its probe that returned to Earth from …
To be fair we have a *very* small sample size (both in terms of mass and in terms of locations on the lunar surface).
Many of those sample locations were chosen to be easy landing sites as well...
We did have one gap, now we have two gaps of just under a billion years each...
Gosh, it sure would've been good to have read about this moon stuff anytime earlier within the last 50yrs of human history. Can you imagine being us so compelled by lunar history instead of the Cold War?
Oh, well... Autopilot and having shiny mylar all over chips and candy is totally worth it.
There are two possibilities in your question. Mass removed form the Moon and transported to Earth, and mass removed form the Moon and sent into space (i.e. not returned to Earth).
I suspect that mining the lunar surface will not have any noticeable effect on Earth's tides or seasons compared to current global warming caused by CO2 and CH4 emissions and the subsequent sea level rise. However, a Texas US congressman did ask their Forestries supremo to work out how to affect the Moon's orbit in order to alleviate high tides. (https://www.theguardian.com/us-news/2021/jun/09/texas-republican-louie-gohmert-climate-change)
I should really have pointed out that in actual fact there is much more mass transferred from Earth to the Moon than the other way. We have left several landers, Lunakhod, Chang'e, a multitude of Apollo landers including some lunar rovers and various orbiters which were crashed into the lunar surface or are still orbiting.
The nett transfer of mass is from Earth to the Moon.
> As an aside, how much mass would need to be removed from the moon to start having an impact on the tides and seasons on earth?
You do know that the moon is moving away from the Earth at a rate of about 3.78 cm per year. That would have a far greater impact on tides than bringing back a few kg of rocks.
As for seasons, the moon does not really have any effect on how seasons work, that is mostly due to earths axial tilt of about 23.44°. When the earth is closest to the sun it is winter time in the northern hemisphere, and summer time in the southern hemisphere. And when the earth is furthest from the sun it is summer time in the northern hemisphere and winter time in the southern hemisphere. Try and spin your head around that for a few minutes! The moon does not really effect the tilt of earths axis.
The fabulously beautiful planet, Bethsellamin, is now so worried about the cumulative erosion caused by ten million visiting tourists a year, that any net imbalance between the amount you eat and the amount you excrete whilst on the planet, is surgically removed from your body weight when you leave.
So every time you go to the lavatory there, it’s vitally important to get a receipt.
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